Control system for electrically heated boiler



United States Patent Of 3,351,739 CONTROL SYSTEM FOR ELECTRICALLY HEATED BOILER Hanford L. Eckman, Dallas, Pa., assignor to The Singer gompany, New York, N.Y.,y a corporation of New erseyr Continuation of application Ser.-No. 449,250, Apr, 19, 1965. This application Nov..21, 1966, Ser. No. 595,994

j 2 Claims; (Cl. 219-321) ABSTRACT oir-.THE DISCLOSURE determined maximum boiler temperature, deactivates the relay and permits theV pump to operate after the relay actuated switches are deenergized. A manual switch permits continuous operation yof the pump.

This application is a continuation of my prior copending application for Electro-Flo Hydronic Boiler Unit,

Ser. No. 449,250, led Apr. 19, 1965 and now abandoned.

One of the paramount features of the present invention is that it comprises an electrically heated boiler unit having electrical controls all of which comprise a small space and which is adaptable to be installed with facility and in which the use of the system requires a thermostat, among other components, so that the control and adjustment thereof is minimal. Further, the invention provides a unit that eliminates flames, smoke, fumes, and lthe causation of clust. The mounting and installation of the apparatus disclosed in accordance with theY preferred embodiment of the invention requires a very small space and is even adaptable to, being entirely mounted on a wall; The size of the" electrically controlled and heated hot water heater unit is comparable to about the size of a portable television set, and is about as heavy as a conventional television set. l

An object, therefore-ofthe present invention also is to provide a hydronic Aboiler unit having the controls capable of controlling and regulating the use of 6000 to 20,000 watts to heat the water which provides about 210,000 B.t.u. per hour to 70,000 B.t.u. per-hour, and which Weighs approximately one-hundred pounds.- A further object of the present invention is to provide a centrally mounted hot Water heating unit to provide 3,351,739 Patented Nov. 7, 1967 ICC ' be the neutral line and this is conveniently shown connected to ground for purposes of simplifying the schematic circuit diagram.

A boiler 14 is shown having a series of VChromalox electrically energized heating elements 16, 16, 16 disposed in the boiler, having one terminal thereof commonly connected to a post 18 of a terminal block 12, and in whichr the other side of the heating elements 16, 16 are connected to respective terminals 22, 24, 26, 28 of microswitches, or small displacement sensitive switches, 30 and which the associated terminals 32 thereof are connected to'post 34 of terminal block 12. All of the terminals 32 are connected in common. v

There are connected in shunt relation to each` ofthe heating elements 1-6, 16 an indicator light 36, 36 respec-` tively for indicating the electrical condition as to kwhether the heatingelementsl are actually energized through the microswitches from the terminal block 12. The neutral line 38 of the terminal block 12 is connected to ground as shown.

Connected to the terminal 32 which is connected directly to terminal post 34 ofthe terminal block 12, there Vis connected a Fusestat fues 40 to provide over-current regu- .Y lation of the control circuit components whichcomprise constant, healthful and easily controlled temperatures the circuit 10. In series =with the fuse 40-also is a limit control switch 44 having terminals 46, 48, 50',terminal 46 being shown as connected to terminal 20 of the microswitches 30. y f

The limit control switch 44 is a single-pole-doublethrowlimit control switch in which terminals 48,-50l are normally closed, but upon certain conditions,V such as whena given temperature or other limit is reached, such as were a limit of 180, or the like, is attained asa set condition, the switch is thrown from terminal 48 to terminal. 46. The limit control switch 44 may be a remote bulb Aquastat controller L 6008A as manufactured by the Honeywell Regulator Company. The limit control switch is actuable by'argiven temperature condition as is remotely sensed by a remote temperature sensing bulb that isv immersed in the lboiler 14. This remote bulb immersion-type controlled operates in response to temperature changes in hydronic heating systems and provides single-pole-double-throw switching for a three wire circuit application, providing limit and circulator control for a pump I62. Thus, it is seen that the pump 62 is energizable upon closure of terminal 20 with terminal 32 and also is energized separately upon attainment of the limit condition, which in the given example may be 180, so that at that limit, the contact 50 is opened with terminal 48 and closes with terminal 46, so that at a given high condition, as sensed by the remotetemperature bulb 60', the pump `62 protectively provides circulation of the boiler water throughout the system until the temperature drops below the limit condition as sensed by the bulb 60.

The limit control switch 44 has its terminal 48 connected to a transformer primary winding 70 which energizes a secondary Winding 72 so that a complete secondary lcircuit provides a roo-m control thermostat V74 in series with a solenoid-microswitches :relay 76 connected invention will become apparent upon full consideration of the following ,detailed description and accompanying drawing in which the sole figure of the drawing is'` a schematic circuit diagram of the electrical circuit and the components thereof comprising the Electro-Flo Hydronic Boiler circuit control system of the preferred-embodiment of the present invention.

Referring now to the drawings there is shown a con-` in series with the secondary winding 72. The solenoidmicro-switches relay 76 maybe an electric heating relay,

such as a'H'oneywell R8154 relay, which-provides, upon `its ene-rgization, such Vas =by secondary winding 72 and vclosure of the contacts of the room thermostat 74, se- .quential actuation Vand closure of terminals 20, Y22, 24,

Y 26, 28 sequentially with terminals 32, 32, etc., so that the switches of the micro-switch are snapped into circuit re-V lation for sequence operation olf-'bringing the heating elements 16, 16, etc., in-to circuit relation without cur-rent surge and fthus reducey the current inrush when the heating element-s are soughtrto be energized by actuation of the micro-switches 30. As canbe understood from the drawing, when the limit control switch 44 is actuated upon attainment of the limit condition, as explained in the preceding paragraph, and continuity between the terminals 50 Iand 48 is broken, the transformer is deenergized thereby deactivating the solenoid-micro-switches relay 76.

The electric heating relay above referred to is used with the two-wire, low voltage thermostat, such as thermostat 74, and a remote mounted transformer 70, 72 to provide control for the multi-stage heating elements of the boiler 14, and it is noted that the progress in switch-closing of the micro-switches 30 progresses from terminal -32 thru 28-32 in sequential fashion, the closing being accomplished in and during respective each .alternate cycle of the alternating current applied through to terminal block 12, i.e., the time interval between the closure of each of the switch terminals 20-32 through 28-32 is measured by the passage `of one cycle of alternatng current. The circuit schematic diagram of FIG. l shows that the relay element 76 provides sequential actuation of the switch terminals 20-32 -thru 28-32, through a sequential switch actuating means as schematically shown by dotted lines 80. 1t is of course within the purview of the present invention to provide a multistage micro-switch of longer periods of actuation or even of slightly shorter periods of actuation than the one cycle delay in the progressive closing of the switch contacts of the micro-switch 30, and it is further within the purview of the present invention to provide the sequential actuation 80 by known equivalent means for progressively or closing step-by-step a series of circuits for energizing a multi-stage load in order to reduce current inrush when the load is energized.

The pump 62 for circulating the water throughout the heating system to which the boiler 14 is connected, said system providing a return of the heated water to the boiler, is energized upon either closure of contacts 20-32 by the micro-switch 30, or by limit actuation of the control switch 44 in which contacts 50-46 are closed, as above described, or by a manual closure of switch 86, which provides ya direct current path from the fuse 40 a-nd the terminal 34 directly through pump 62 so that the pump is actively energized.

Thus, it is seen that when the environmental condition about the room thermostat 74 becomes sufciently cool, the thermostat 74 is caused to close, performing a cornplete loop and circuit for secondary winding 72 so that there :commences a sequential actuation and closure of all of the multi-stages 20-32 thru 28-32 of micro-switch 30, so that in this way pump 62 becomes energized, and the load or heating elements 16, 16, 16, 16 lsequentially become energized without any substantial overload of the current supplied from terminal board 12, and in this way the water in the boiler 14 is commenced to be heated. The pump 62, in a well known manner, provides circulation of the hot water in the boiler 14, and eventually the environmental temperature of the room in which room thermostat 74 is located is elevated to the point where the micro-switches 30 are opened. Micro-switches 30 being opened, pump 62 is dis-connected `from the circuit, unless the limit conditions lof Icontrol switch 44 are reached, in which case the pump continues to circulate until the limit -conditions of control switch 44 Vare not exceeded and then pump 62 is taken out of the line circuit.

Additional embodiments of the invention in this specification will occur to others and therefore it is intended that the scope of the invention be limited only by the appended claims and not by .the embodiment described hereinabove. Accordingly, reference should be made to the `following claims in determining the full scope of the invention.

Having thus described the nature of this invention, what is claimed herein is:

1. A control system for an electric hot water house heating system having a boiler, a plurality of electric heating elements mounted within said boiler to heat the water therein and pump means -for circulating the water through a predetermined path in the electric hot water house heating system, said control system comprising a source of electrical energy utilizing alternating current and means for selectively energizing and deenergizing said plurality of heating elements and said pump means comprising switch means for sequentially energizing in a single complete continuous operation first said pump means and then one by one all of said heating elements and sequentially deenergizing in a single complete continuous operation one by one all of said heating elements and then said pump means, said switch means including a plurality of small displacement sensitive switches, solenoid relay means and sequential switch actuation means responsive to said relay means for sequentially actuating said small displacement sensitive switches, an electrical transformer having a primary and a secondary coil, a room thermostat connected in series with the secondary coil of said electrical transformer and the solenoid of said solenoid relay means, `a limit control switch, temperature sensing means responsive to the temperature of the water in the boiler for actuating said limit control switch at a predetermined maximum water temperature, said limit control switch having a pair of circuit closing positions, said iirst limit control switch position being effective below said predetermined maximum water temperature to complete a circuit between said transformer primary coil and said source of electrical energy and said second limit control switch position being effective at said predetermined maximum water temperature to actuate said pump means to maintain the water circulation until the water temperature as sensed by said temperature sensing means drops below said predetermined maximum temperature, whereby said thermostat activates said solenoid relay means when the thermostat environment reaches a predetermined low temperature thereby rapidly energizing said pump means and all of said heating ele- -ments in sequence and said thermostat deactivates said solenoid rel-ay means when said thermostat environment reaches =a predetermined high temperature thereby rapidly -deenergizing all of said heating elements and said pump means in sequence.

2. A control system as in claim 1 including a manually actuable normally open switch connected to said pump means and said source of electrical energy, whereby upon actuation of said manually actuable switch said pump means is continuously operated, and means connected to said heating elements for providing a visual indication of the energization of said electric heating elements.

References Cited UNITED STATES PATENTS 1,256,950 2/1918 Thompson et al. 335-121 2,450,399 9/1948 Sheidler 219-453 2,498,054 2/1950 Taylor 219-493 X 2,553,212 5/1951 Rouis et al. 219--321 2,700,505 1/l955 Jackson 219--493 X 3,031,559 4/1962 Harmon et al. 219-321 X ANTHONY BARTIS, Primary Examiner` 

1. A CONTROL SYSTEM FOR AN ELECTRIC HOT WATER HOUSE HEATING SYSTEM HAVING A BOILER, A PLURALITY OF ELECTRIC HEATING ELEMENTS MOUNTED WITHIN SAID BOILER TO HEAT THE WATER THEREIN AND PUMP MEANS FOR CIRCULATING THE WATER THROUGH A PERDETERMINED PATH IN THE ELECTRIC HOT WATER HOUSE HEATING SYSTEM, SAID CONTROL SYSTEM COMPRISING A SOURCE OF ELECTRICAL ENERGY UTILIZING ALTERNATING CURRENT AND MEANS FOR SELECTIVELY ENERGIZING AND DEENERGIZING SAID PLURALITY OF HEATING ELEMENTS AND SAID PUMP MEANS COMPRISING SWITCH MEANS FOR SEQUENTIALLY ENERGIZING IN A SINGLE COMPLETE CONTINUOUS OPERATION FIRST SAID PUMP MEANS AND THEN ONE BY ONE ALL OF SAID HEATING ELEMENTS AND SEQUENTIALLY DEENERGIZING IN A SINGLE COMPLETE CONTINUOUS OPERATION ONE BY ONE ALL OF SAID HEATING ELEMENTS AND THEN SAID PUMP MEANS, SAID SWITCH MEANS INCLUDING A PLURALITY OF SMALL DISPLACEMENT SENSITIVE SWITCHES, SOLENOID RELAY MEANS AND SEQUENTIAL SWITCH ACTUATION MEANS RESPONSIVE TO SAID RELAY MEANS FOR SEQUENTIALLY ACTUATING SAID SMALL DISPLACEMENT SENSITIVE SWITCHS, AN ELECTRICAL TRANSFORMER HAVING A PRIMARY AND A SECONDARY COIL, A ROOM THEREMOSTAT CONNECTED IN SERIES WITH THE SECONDARY COIL OF SAID ELECTRICAL TRANSFORMER AND THE SOLENOID OF SAID SOLENOID RELAY MEANS, A LIMIT CONTROL SWITCH, TEMPERATURE SENSING MEANS RESPONSIVE TO THE TEMPERATURE OF THE WATER IN THE BOILER FOR ACTUATING SAID LIMIT CONTROL SWITCH AT A PREDETERMINED MAXIMUM WATER TEMPERATURE, SAID 